$Id: 016_ICE_subprotocol_reply_fix.diff 1044 2004-02-16 17:40:33Z branden $

This patch by Jochen Voss.

  DESCRIPTION OF THE PROBLEM:

  When two hosts communicate over an ICE connection and use
  different major opcodes for a subprotocol, it is impossible
  to use message replies.

  Let HOST-A and HOST-B be two hosts which communicate over an
  ICE connection and use a subprotocol PROT.  Both have
  obtained an opcode for PROT, HOST-A got the opcode 1 from
  `IceRegisterForProtocolSetup' and HOST-B got the opcode 2
  from `IceRegisterForProtocolReply' (he uses several
  protocols simultaneously, so the value is not 1).

  Now HOST-A sents a message wich requires a reply.  In order
  to do so he sets up an `IceReplyWaitInfo' and calls
  `IceProcessMessages':

      IceReplyWaitInfo  reply_info;
      Bool  reply_ready;

      reply_info.sequence_of_request = IceLastSentSequenceNumber (ice_conn);
      reply_info.major_opcode_of_request = opcode;
      reply_info.minor_opcode_of_request = PROT_Question;
      reply_info.reply = reply;

      do {
	  IceProcessMessagesStatus  process_status;

	  process_status = IceProcessMessages (ice_conn,
					       &reply_info, &reply_ready);
	  ...
      } while (! reply_ready);

  The `reply_info.major_opcode_of_request' field contains the
  value 1, now.

  Next, HOST-B's reply arrives while HOST-A is executing the
  function `IceProcessMessages'.  Within this function, the
  `reply_wait' is registered via the command

      _IceAddReplyWait (iceConn, replyWait);

  This makes ICE wait for something with major opcode 1.  But
  the variable `header' has `header->majorOpcode == 2',
  because HOST-B sent it this way.  So the following call

	  useThisReplyWait = _IceSearchReplyWaits (iceConn, header->majorOpcode);

  (also from `IceProcessMessages') does not find my
  `reply_wait' because ICE searchs for the major opcode 2, not
  1!  I think this is a bug in the ICE library.

Not submitted upstream yet.

--- xc/lib/ICE/process.c~	2003-01-01 17:27:29.000000000 -0500
+++ xc/lib/ICE/process.c	2003-01-01 17:32:09.000000000 -0500
@@ -247,16 +247,33 @@
 
 	_IceAddReplyWait (iceConn, replyWait);
 
-
 	/*
 	 * Note that there are two different replyWaits.  The first is
 	 * the one passed into IceProcessMessages, and is the replyWait
 	 * for the message the client is blocking on.  The second is
 	 * the replyWait for the message currently being processed
 	 * by IceProcessMessages.  We call it "useThisReplyWait".
+	 *
+	 * Also, when two hosts communicate over an ICE connection and use
+	 * different major opcodes for a subprotocol, it is impossible
+	 * to use message replies unless we translate opcodes before
+	 * comparing them.
 	 */
+	
+	{
+	    int op;
 
-	useThisReplyWait = _IceSearchReplyWaits (iceConn, header->majorOpcode);
+	    if (header->majorOpcode == 0)
+	    {
+		op = 0;
+	    }
+	    else
+	    {
+		int idx = header->majorOpcode - iceConn->his_min_opcode;
+		op = iceConn->process_msg_info[idx].my_opcode;
+	    }
+	    useThisReplyWait = _IceSearchReplyWaits (iceConn, op);
+	}
     }
 
     if (header->majorOpcode == 0)